Infrared sensor arrays, such as those used for portable infrared cameras or other devices, are often implemented as a focal plane array having microbolometers formed on top of a substrate. Such microbolometer arrays are becoming widespread in thermal imaging applications due to their relatively small pixel dimensions and the relative simplicity of the supporting readout integrated circuit (ROIC). However, although such microbolometer arrays may permit high-resolution thermal imaging in a small package and at a low cost, they typically cannot be relied upon to acquire an accurate temperature reading due to their sensitivity to ambient temperature changes and their relative low temperature resolution (e.g., only accurate to approximately ±2° F. in one implementation).
While other types of infrared sensors may provide a more accurate and/or stable temperature determination, those other types of infrared sensors generally require more complex structures and supporting circuits, have larger pixel dimensions, and/or otherwise are more complex and costly to implement in a sensor array for thermal imaging. For example, a thermopile infrared sensor (e.g., a sensor element formed by grouping one or more thermocouples together) may be more stable over a wider temperature range and have a better temperature resolution than a bolometer-based sensor, but typically requires a more complex readout circuit and a larger pixel size to achieve a desired sensitivity, and thus may not be suitable for implementing a compact, low-cost, yet high-resolution thermal imaging array.